Recently, portable appliances such as notebook personal computers and cellular phones have become widely used, and there is thus an increasing demand for batteries as the power source for portable appliances. In particular, there is an increasing demand for secondary batteries that are compact and light-weight, have high energy density, and can be repeatedly charged and discharged.
To meet such demand, non-aqueous electrolyte secondary batteries are being actively studied and developed. Since non-aqueous electrolyte secondary batteries contain large energy due to an increase in the functionality of portable appliances, they generate large amounts of heat in the event of abnormal conditions.
Thus, proposals have been made on the structure of a battery pack containing such batteries, in order to suppress, when one of the batteries generates abnormal heat for some reason, the conduction of the heat to adjacent batteries.
PTL 1 proposes separating batteries by a partition plate comprising a flame-retardant resin.
In order to make the partition plate more flame-retardant, PTL 2 proposes using inorganic refractory materials such as mica and ceramics.